*,

body {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.container {
    margin: 0;
    width: 100%;
    height: 100%;
    background-color: #dfe6e9;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.calculator {
    padding: 20px;
    border-radius: 10px;
    background-color: #636e72;
     
}

.calculator form input {
    outline: none;
    border: none;
    width: 60px;
    height: 60px;
    border-radius: 8px;
    margin: 10px;
    font-size: 17px;
    color: #636e72;
    text-align: center;
    cursor: pointer;
    box-shadow: -8px -8px 15px;
}

form .display {
    display: flex;
    justify-content: flex-end;
}

form .display input {
    flex: 1;
    text-align: right;
    padding-right: 16px;
    font-size: 22px;
}

form input.equal {
    width: 145px;
}